Thermology studies the thermal exchanges between bodies and understands the transformations and transfers of energy between one system and another.
• Temperature: temperature is an index of the degree of thermal agitation of the atoms or molecules that make up a body; it is therefore connected to the concept of kinetic energy.
• Heat: heat is a way of transferring energy.
There is therefore a substantial difference between the concept of heat and that of temperature.
There are various methods of measuring how hot or cold a body is:
• Thermal expansion: to measure how hot or cold a body is, it is necessary to resort to a phenomenon that always repeats itself in the same way, that is, thermal expansion; when heated, all bodies dilate, that is, increase their volume.
• Thermoscope: instrument that exploits the phenomenon of thermal expansion and that allows you to check the temperature variations.
• Thermometer: instrument that allows you to quantitatively measure the thermal state of a body, ie its temperature.
• Zero principle of thermodynamics: allows to define the state of thermal equilibrium between two bodies.
When a hot body A is placed in contact with a cold body B, after a certain period of time, the two bodies reach thermal equilibrium, i.e. the same temperature. When a body A is in thermal equilibrium with a body T and given a body B also in equilibrium with the body T, bodies A and B are said to be in equilibrium with each other.
Thermometric scales:
The Celsius scale considers two physical phenomena that always occur with the same characteristics: the melting of ice in equilibrium with water at the pressure of 1 atm and the boiling point of water at the pressure of 1 atm; these two phenomena have been attributed the value 0 and 100.
In the Fahrenheit scale, the numbers 32 and 212 correspond respectively to the 0 and 100 of the centigrade scale. It took a mixture of ice and salt as the value 0, while the average temperature of the human body as the value 100, but was subsequently modified because the two values were not constant, so he used the fixed points of Celsius as a reference.
Linear thermal expansion:
Thermal expansion can be linear, superficial and volumic, and can be applied to solid, liquid and gaseous bodies.
The linear thermal expansion is applied to those bodies that have a single predominant size compared to the others. FORMULATION THERMOLOGY We take a metal rod at 0 ° C and measure its length lo; we heat the body bringing it to a high temperature. We can observe that the bar has lengthened. The elongation is valid: Δl = lT –lo. The elongation is directly proportional to the initial length and the final temperature.
The thermal expansion:
When the temperature rises, the bodies dilate in all three dimensions: length, width and height. We therefore speak of volume expansion.
• Temperature: temperature is an index of the degree of thermal agitation of the atoms or molecules that make up a body; it is therefore connected to the concept of kinetic energy.
• Heat: heat is a way of transferring energy.
There is therefore a substantial difference between the concept of heat and that of temperature.
There are various methods of measuring how hot or cold a body is:
• Thermal expansion: to measure how hot or cold a body is, it is necessary to resort to a phenomenon that always repeats itself in the same way, that is, thermal expansion; when heated, all bodies dilate, that is, increase their volume.• Thermoscope: instrument that exploits the phenomenon of thermal expansion and that allows you to check the temperature variations.
• Thermometer: instrument that allows you to quantitatively measure the thermal state of a body, ie its temperature.
• Zero principle of thermodynamics: allows to define the state of thermal equilibrium between two bodies.
When a hot body A is placed in contact with a cold body B, after a certain period of time, the two bodies reach thermal equilibrium, i.e. the same temperature. When a body A is in thermal equilibrium with a body T and given a body B also in equilibrium with the body T, bodies A and B are said to be in equilibrium with each other.
Thermometric scales:
The Celsius scale considers two physical phenomena that always occur with the same characteristics: the melting of ice in equilibrium with water at the pressure of 1 atm and the boiling point of water at the pressure of 1 atm; these two phenomena have been attributed the value 0 and 100.
In the Fahrenheit scale, the numbers 32 and 212 correspond respectively to the 0 and 100 of the centigrade scale. It took a mixture of ice and salt as the value 0, while the average temperature of the human body as the value 100, but was subsequently modified because the two values were not constant, so he used the fixed points of Celsius as a reference.
Linear thermal expansion:
Thermal expansion can be linear, superficial and volumic, and can be applied to solid, liquid and gaseous bodies.
The linear thermal expansion is applied to those bodies that have a single predominant size compared to the others. FORMULATION THERMOLOGY We take a metal rod at 0 ° C and measure its length lo; we heat the body bringing it to a high temperature. We can observe that the bar has lengthened. The elongation is valid: Δl = lT –lo. The elongation is directly proportional to the initial length and the final temperature.
The thermal expansion:
When the temperature rises, the bodies dilate in all three dimensions: length, width and height. We therefore speak of volume expansion.
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